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DrVenkman last won the day on July 7 2019

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About DrVenkman

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    Back off, man! I'm a scientist.
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    "I love the smell of flux in the morning. Smells like ... continuity!"
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  1. Find a copy of @phaeron’s Altirra Hardware Reference Manual - it’s got lots of stuff like that documented.
  2. It’s a keypad to the left of the rotary controller. Hey Ed - sign me up. I may have to sell a kidney or something but it looks glorious.
  3. An Uno Cart will juuuust fit under the cover of the 1050 case. And with Jon’s latest firmware allowing you to disable and re-enable the cart ROM, you can leave it in permanently. That’s what I’ve done since my prototype was completed.
  4. Scott Baker's Masterplay clone works great with a 3-button Genesis pad too - the second Fire button on the 5200 can be used with wither C button on the Genny pad or a button on the keypad.
  5. That's the controller that I and my friend @MakerMatrix built and sold for about 3 months this past winter. While we sold a good number of them and had a great deal of community support, the fact is the design requires a lot of hand-soldering and assembly and it just became too onerous to continue after the big holiday season crush that took care of our backorder list and the next few dozen. If folks missed out, we're very sorry. We may resume production in the future but we are nowhere near ready to announce anything or discuss it at this point. But thank you for your interest.
  6. The diode isn’t for overvoltage. It’s to isolate the rest of the devices on the SIO bus from essentially being “locked out” of the bus traffic by the interface device. Lots of details and discussion about this on the SDrive-MAX threads.
  7. That’s the problem - the Atari boots up faster than the Arduino gets up and running. You either need to alter your device for external power and have it running before the Atari boots, or do some kind of mod to your Atari that lets you cold boot without a power cycle.
  8. If the mod is done correctly so that it combines the audio in line from the cartridge port, it should. So basically, if you do the mod such that you can hear audio from Ballblazer, Commando or any of the modern POKEY homebrews (or Rikki & Vicki!) you should hear XM audio.
  9. If you want to have more fun with your scope, compare the several LUM outputs of the TIA with SYNC; or as here, the Chroma output of the UAV (yellow) versus Luma (purple) taken while displaying a color bar test pattern. And with the Chroma signal hidden, look how wonderfully sharp the Luma level transitions are from the UAV.
  10. Or just dunk them all in 90% iso (which is what docs swab your skin with for an injection after all ). Besides, unless they arrive <72 hours after they are shrink wrapped, your risk is essentially zero anyway. Viruses generally don’t live long without a host to replicate in. EDIT: saw another study that suggests a week. So Lysol then iso bath.
  11. Photos of peoples’ work would help. Again, for at least the third time, the UAV should have zero impact on the general functioning of the computer. The system can operate completely fine with no video output, and the UAV picks up all its signals from “downstream” of the IC’s that cause the computer to run and operate. It uses LUM, SYNC and COL signals from the GTIA and merely intercepts them before they run through the stock Atari video components. If your system doesn’t work after you’ve installed the UAV, you’ve shorted something or damaged the motherboard in some way.
  12. UAV from @MacRorie at The Brewing Academy for composite and/or S-video is the go-to for many folks. Of course for an NTSC 600XL you either need to install a video jack or some RCA connectors, or something along those lines.
  13. I ordered a UAV a few weeks ago to put into one of my 5200's and got one of Marlin's printed manuals but I didn't pay it much mind - I've installed too many of these things into too many computers (800XL, two 1200XL's, 1088XEL, 1088XLD, 2600, 7800 and now a 5200) to worry about where the composite, chroma and luma and ground connections go to the UAV. Jumper configurations for the computers and 5200, sure, and close attention to where to solder the LUM, SYN and COL wires into the UAV if installing without a terminal block. But those locations are silkscreened onto the bare boards of the Rev D's so it's no trouble at all. Anyway, glad the OP got the issue resolved. As an aside, I discovered something interesting today while moving some connections around on my Incognito 800 and a C1902 monitor: that particular monitor doesn't care one whit whether you feed it a composite or bare chroma signal into the Chroma connection on the monitor; so long as you have Luma connected too, you get a lovely crisp S-video display, utterly indistinguishable from feeding it the proper Composite signal. So in other words, a stock Atari XL without a separate Chroma signal on the jack would've still given you an S-video display! Conversely, if you feed it a Chroma signal into the Composite jack, it won't work at all because you don't have a sync signal on the Chroma line. I need to try this with my C1702 monitor as well. If it works the same, it might do a bit to explain to incredulous modern minds why Atari dropped the separate Chroma signal from XL computers.
  14. Okay, so I broke open one of my 2600's and took some scope readings (pardon the phone pics - didn't have a USB stick handy to do straight screencaps from the scope). Remember, pin 9 is the video Color data, which has to follow your local (analog) television signal spec. So I pulled up a color test program on my Harmony Cart and measured the output. When you zoom out far enough, you'll see not just the clock-by-clock modulation of the signal for the color, but also the horizontal blank and the vertical blank as well. But if you're familiar at all with how the 2600 draws on the screen, every bit of this is definable by the program running. The "kernel" used by the programmer is the heartbeat of the program, so to speak, and it has to conform to the basic limits of the analog signal the system was intended for (NTSC, PAC, SECAM ...). There's some wiggle room because analog TV's tended to be more forgiving than today's digital stuff. So here zoomed in far enough, you can see 16 repeating cycles on pin 9, followed by a period of COL going high again (I didn't measure that period). Were I to zoom out the horizontal scale, I would see the image you get on your scope in your first post. That "mess" you see is the where your scope is trying to capture a signal that's not really following the same predictable frequency at the range you're capturing - think of a blurry photo; the exposure is too long to freeze the motion, if you get the analogy. And the COL signal is definitely not a simple, predictable single frequency. It's the NTSC colorburst frequency, being modulated to display the contents of whatever the program is trying to show on that particular scanline. But zoomed out from my first photo, you can see the 15.75 khz horizontal frequency (my measurements are quick and dirty with manually-set cursors; I could've zoomed in closer and gotten more precise but you get the idea). Similarly, when I zoom out in the time base even further, you can see that this program's kernel seems to be creating a 59.9 Hz progressive image instead of a 29.97 Hz interlaced image. Not sure whether that's a measurement artifact because I'm connected to a 60 Hz flat panel screen or if I just missed a drop in the signal in the middle of all that data. EDITED TO ADD SOME MORE STUFF: So I got curious and set the test pattern cart to show different patterns. Take a look at this one: Now look at the COL signal between that 15.75 khz horizontal trace: Whaddaya know - 10 pulses on the scanline, each one corresponding to one of 10 vertical lines. Now check the next test pattern: And we see exactly what we should - a single pulse right in the middle of the scanline: And finally, if you simply let the scope try to track the main frequency (the "messy" images above), you'll see exactly what you should: the base 3.57 MHz NTSC colorburst frequency that's being modulated by the TIA chip to produce the image, scanline by scanline down the screen:
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